This invention relates to solid polyurethane compositions for encapsulating, embedding or surface protective coating a solid article to which future access (reentry) is desired, and also to a two part package assembly for manufacturing said polyurethane composition, said assembly consisting of a package of liquid polyurethane prepolymer composition and of a liquid curing solution therefor.
Since approximately 1955, when the initial use of plastic sheath telephone cable began to be used by the operating telephone companies in the United States, there have been a variety of methods and techniques concerning the protection of splice connections. These have varied from such devices as hermetically sealed metal and plastic cases, to multiple layers of tape wrappings, adaptation of lead sleeving, plastic and metal devices having rubber and neoprene grommets, as well as total encapsulation in many varied closures using such diversified fillers as paraffin, wax, tar, epoxy, and polyurethanes. More recently, there have been a number of attempts to utilize polyethylene jelly and variations of this type material for waterproof encapsulation of wire connections. However, these polyethylene materials are not entirely reenterable and are not satisfactory.
The ever increasing application of buried wire and cable has brought about the requirements to develop a more foolproof closure method for both new splicing as well as repair of damaged wire and cable that would result in extremely high waterproof integrity, yet not involve undue cost for materials nor excessive time in labor required to do the work. To date, for one reason or another, none of the closure systems offered meet all of the demanding requirements of the operating telephone companies, namely, a closure system that is quickly reenterable, safe on any type plastic insulated wire, simple and quick to use, and inexpensive.
The material which most nearly met the above requirements was developed a few years ago and is a soft cable jelly, commercially available as ICKYPIC II Cable Jelly. Unlike other jellies, this material could be safely used on older polyethylene insulated conductors, as well as on the newer polypropylene insulated conductors. This meant that it could be applied on all existing plastic sheath cables used since 1955 in the Telephone Industry throughout the United States. Although highly successful, it sticks to the workmen's tools, clothes, other pieces of materials and is objectionable on that basis. While meeting many desirable requirements as previously mentioned above, it was obviously not a satisfactory solution for waterproof encapsulation of telephone cable and service wire splices.